chore: add PR checklist to pr template (#2434)

.github/PULL_REQUEST_TEMPLATE.md

@@ -3,14 +3,30 @@ Thank you for your pull request! Please review the requirements below
 and ensure your pull request has fulfilled all requirements outlined in the target package.
 -->
 
+## PR checklist
+
+For every PR, make sure that these statements are true:
+- [ ] Includes only changes relevant to the original ticket. Significant refactoring needs to be separated.
+- [ ] Doesn't contain type casts and non-null assertions.
+- [ ] Doesn't add `@ts-ignore`.
+- [ ] Doesn't disable lints.
+- [ ] Doesn't use `useState` just for computation - use plain variables instead.
+- [ ] Splits components into pure components that don't depend on external state or hooks.
+- [ ] Avoid embedding components within other components
+- [ ] Doesn't propagate optional values without good reason, doesn't mark property values as optional if that doesn't represent reality.
+- [ ] Doesn't duplicate existing code.
+- [ ] Parses out-of-domain data - this includes user input, API respones, on-chain data etc.
+- [ ] Doesn't contain commented out code.
+- [ ] Doesn't contain skipped or empty tests.
+
+Subjective - at the discretion of the reviewers
+- Does things as simply as possible, but not simpler.
+- Doesn't reinvent the wheel or create premature abstractions.
+
 ##### Description
 
 <!-- Describe your changes here. -->
 
 ##### Refers/Fixes
 
-<!-- If this PR is related to a GitHub issue, please add a link here. -->
-
-##### Testing
-
-<!-- All PRs should be accompanied by tests! If you haven't added tests, please explain here. -->
+fixes #issuenumber